ANITA™ Mox deammonification process for COD-rich and THP reject water

Higher N-removal performances using the integrated fixed film activated sludge (IFAS) ANITA Mox™ configuration were obtained at higher soluble biodegradable COD (sbCOD) to N ratios for conventional reject water due to increased denitrification activity in suspended growth, compared to the ANITA Mox moving bed biofilm reactor (MBBR) configuration. Anammox were still very active in the biofilm after more than 10 months of operation despite heterotrophs present mostly in the IFAS suspended phase. Both bench and pilot scale tests of the IFAS ANITA Mox process treating thermal hydrolysis process (THP) reject water also provided very promising results with N-removal rate up to 4 gN-NH4/m2.d with 1:3 dilution. The inhibitory effects of THP reject water on the overall N-removal performance, while confirmed, can effectively be overcome with an appropriate dilution rate, especially since spare hot process water is usually available on site from the heat exchanger required to cool sludge after the THP stage. The very good N-removal performances obtained under “unfavorable” sbCOD/N ratio conditions with the use of IFAS operating mode open new roads for the application of the ANITA Mox process for the treatment of industrial effluents with organic matter and for THP post-digestion reject water.